Electrographic fusing apparatus and method

Abstract

Loose toner particles carried by a flexible support are fused thereto by cylindrically curling the support about the longitudinal axis of a flashlamp, and momentarily energizing the flashlamp while the toner-bearing support is curled thereabout. A transport mechanism, adapted for use in a high-speed recording apparatus, advances a toner-bearing sheet along a circular path such that the toner-bearing surface of the sheet is untouched and continuously faces toward the center of curvature of the path.

I claim: 
     
       1. An improved flash fusing apparatus for fusing toner images onto a copy sheet comprising: an elongated flashlamp,   a cylindrically shaped member circling said flashlamp along the longitudinal axis thereof, and   means for positioning a copy sheet bearing toner images along the cylindrical member to form a circular path around said flashlamp whereupon energizing said lamp uniform direct radiation is imparted to the sheet to fuse the toner particles at a reduced power output.   
     
     
       2. Apparatus according to claim 1 including sensing means for detecting the lead edge of sheet to provide a signal to energize the flashlamp. 
     
     
       3. The invention according to claim 1 wherein said flashlamp comprises a xenon flashlamp having a pulse width of between 0.25 and 1.5 milliseconds and operating at an input power level of between 600 and 800 joules. 
     
     
       4. The invention according to claim 1 wherein said positioning means includes an endless web composed of a dielectric material, means for imparting an electrostatic charge to said web to render said web attractive to such a sheet and means for advancing said web around said flashlamp. 
     
     
       5. The invention defined in claim 1 wherein said flashlamp is adapted to emit a pulse of high intensity radiant energy comprised primarily of wavelengths that are substantially reflected by a paper copy sheet positioned by said positioning means and substantially absorbed by such toner images on that sheet whereby radiant energy from said flashlamp will be reflected by non-image bearing portions of such sheet toward other portions of such sheet.